Discussion:
Q1. Sixty-four students in an introductory college economics class were asked how many credits they had earned in college, and how certain they were about their choice of major. Research question: At a= .02, is the degree of certainty independent of credits earned?
Observed frequencies
Credits Earned Very Uncertain Somewhat Certain Very Certain Row Total
0-9 12 8 3 23
10-59 8 4 9 21
60 or more 1 7 12 20
Col Total 21 19 24 64
Step 1: State the null and alternate hypotheses
Step 2: Select level of significance
a = 0.2
Step 3: Identify the test statistic and state its formula
Χ2= ni=1Σ(fi-ei)2/ei
Step 4: Formulate a decision rule
Step 5: Make a decision
Q2. A student team examined parked cars in four different suburban shopping malls. One hundred vehicles were examined in each location. Research question: At a= .025, does vehicle type vary by mall location?
Observed frequencies
Vehicle Type Somerset Oakland Great Lakes Jamestown Row Total
Car 44 49 36 64 193
Minivan 21 14 18 13 66
Full-sized Van 2 5 4 2 13
SUV 19 26 25 12 82
Truck 14 6 17 9 46
Col Total 100 100 100 100 400
Step 1: State the null and alternate hypotheses
Step 2: Select a level of significance a = 0.025
Step: 3 Identify the test statistic and state its formula
Χ2= ni=1Σ(fi-ei)2/ei
Step: 4 Formulate a decision rule
Step: 5 Make a decision